Biomedical subjects

Dominik Riss

Publications and source records attributed to Dominik Riss.

3 recordsLinked to original sources

PubMed2005

Galectin-3 Expression in Functioning and Silent ACTH-Producing Adenomas.

Galectin-3 (Gal-3), a beta galactoside-binding protein, has been implicated in a variety of biological functions including cell growth, differentiation, tumor cell adhesion, angiogenesis, tumor progression, and metastasis. We recently reported that Gal-3 was expressed in a subset of normal pituitary cells and tumors including PRL, ACTH, and in folliculo-stellate (FS) cells and tumors and that Gal-3 had an important regulatory role in pituitary cell proliferation. We further investigated the expression of Gal-3 protein in ACTH- and PRL-producing tumors and the expression of various galectin mRNAs by RT-PCR in pituitary adenomas and normal pituitary. Most silent ACTH subtypes 1 and 2 adenomas were negative or only focally positive for Gal-3 expression compared to functioning ACTH tumors from patients with Cushing's disease and Nelson's syndrome. In the normal pituitary, Gal-3 was expressed in less than 1% of the basophil-invading cells (ACTH cells present in the posterior pituitary) and in a subset of the anterior lobe ACTH-positive cells. RT-PCR analyses showed that many members of the galectin family including galectins 1, 2, 3, 4, 5, 6, 7, 8, and 9 were expressed in normal pituitary and in functioning ACTH- and PRL-producing tumors. These results indicate that Gal-3 is associated with functioning ACTH and PRL tumors and is expressed infrequently in silent ACTH adenomas, suggesting that Gal-3 protein and/or gene is altered in non-functioning ACTH tumors. The use of ACTH and Gal-3 immunostaining should help in the diagnosis of silent ACTH adenomas.

ACTH-Secreting Pituitary Adenoma↗

PubMed2003

Differential expression of galectin-3 in pituitary tumors.

Galectin-3 (Gal-3), a beta-galactoside-binding protein, has been implicated in a variety of biological functions, including cell proliferation and differentiation, tumor cell adhesion, angiogenesis, apoptosis, tumor progression, and metastasis. We investigated the role of Gal-3 in the development and progression of pituitary tumors. Immunohistochemical and Western blot analysis of normal and neoplastic human pituitaries showed that only lactotroph (PRL) and corticotroph (ACTH) hormone-producing cells and tumors expressed Gal-3. Gal-3 was present in 24 of 38 (63.2%) PRL adenomas, 5 of 6 (83.3%) PRL carcinomas, 19 of 41 (46.3) ACTH adenomas, and 7 of 8 (87.5%) ACTH carcinomas, but not in 112 other pituitary adenomas and carcinomas. Pituitary folliculo-stellate cells, which have macrophage-type functions in the anterior pituitary, also expressed Gal-3. Hyperplastic and neoplastic pituitaries from p27(Kip1) (p27)-null mice, which produce mainly ACTH, showed increased Gal-3 expression levels compared with control mice. Treatment with transforming growth factor beta1, which regulates pituitary cell proliferation, reduced Gal-3 as well as p27 expression levels in cultured HP75 pituitary cells and Gal-3 in cultured pituitary cells from p27-null mice, suggesting that p27 is not necessary for the inhibitory effects of transforming growth factor beta1 on the cell cycle in the pituitary. The role of Gal-3 in pituitary cell function was examined by RNA interference experiments. Inhibition of Gal-3 gene expression by RNA interference decreased HP75 cell proliferation and increased apoptosis. These results indicate that Gal-3 has an important role in pituitary cell proliferation and tumor progression.

Adenoma↗

PubMed2003

Galectin-3 expression in normal, hyperplastic, and neoplastic endometrial tissues.

This study evaluated the expression of galectin-3 in 101 curettage specimens from normal, hyperplastic, and neoplastic endometrial tissues using immunohistochemistry. The histologic diagnoses were as follows: normal proliferative (n = 8) and secretory (n = 4) phase, simple hyperplasia (SH, n = 16), complex hyperplasia without atypia (CH, n = 11), atypical hyperplasia (AH, n = 13), endometrioid adenocarcinoma (EC, n = 35), serous papillary carcinoma (SPC, n = 10), and clear cell carcinoma (CC, n = 4). Immunostaining was scored with regard to the approximate percentage of positive tumor cells and relative staining intensity. The scores of immunostaining increased significantly from NE, SH, CH, and AH to the adenocarcinomas (ANOVA, p < 0.0001). Subsequently, three significantly different levels of galectin-3 expression were found (Newman-Keuls multiple comparison test). These consisted of (a) NE, SH, and CH, (b) AH and EC, and (c) SPC and CC. Galectin-3 expression increased with tumor grade (ANOVA, p = 0.0026). The scores of FIGO stages I to III did not differ significantly (ANOVA, p = 0.1687). Enhanced nuclear galectin-3 expression was noted in carcinomas, immunostaining of stromal cells decreased in the latter. This study shows that galectin-3 expression increases from normal and hyperplastic to atypical hyperplastic and cancerous states of endometrial tissues, and provides further evidence of a relationship between AH and EC.

Adult↗